#7.1 Kotlin Functions Basics and Syntax Video Lecture - Kotlin Tutorial

hi Lisa strings at the earth once again
welcome to the next video of Cortland
fundamentals now in this video let us
now proceed and check out what is the
syntax to define functions in Kotlin so
a typical method in case of Cortland
appears to be like this
so we have a fun keyword this method
name these are the arguments and this is
the return type and then here we return
something so a typical method in case of
Cortland has some syntax such as this is
the fun keyword this is the method name
these are the formal parameters such as
length and breadth and here at the end I
have a return type now to define a
return type you have to simply use a
colon followed by space and followed by
the return type such as integer string
boolean and so on and now here with the
help of this method we are actually
finding the area of a rectangle or
something like that
so here I am simply returning length
into breadth which is equivalent to an
integer value that we have defined here
now apart from return type the methods
can also return void that is it has also
got the right to return nothing so for
that the syntax is this right so here
function find area length and breadth
and here instead of void in Cortland we
are using unit so this unit is actually
equivalent to the void in Java right so
if you do not want to return anything in
Cortland then simply use colon space
unit now as per the cortland coding
convention if you return nothing then
you don't need to define this unit
explicitly here by default if you don't
define anything here then also the code
will work so if you want you can also
remove this unit from here it is of no
use and now inside the IntelliJ IDE
inside our kt file let us try to write
our first function let's say fu n space
a function to add two numbers right
simply define the method
body and write your code inside this so
here I will simply define the variable
of let's say a equal to 2 and then where
be equal to let's say 4 and now here I
will simply print the sum of these two
numbers or if you want you can also
define where some equal to a plus B like
this and then finally and then finally
at the end I will simply print the sum
such as sum is let's say a plus B or
instead of this you can also use the
interpolation that is the string
interpolation that we studied in the
previous videos right so curly bracket
open and close along with a prefix of
dollar sign and I guess I forgot to use
the sum variable here so as of now let
us remove this right so this completes
our code now the question arises from
where we are going to call this method
of add we don't have any main method
defined in case of Kotlin so here I will
simply define my top-level main method
which is actually equivalent to public
static void main
in case of Java programming so let us
define the fun main a argyus
: array of string right as simple as
that and we already know all these
things from the previous videos of this
course so simply call this add method
and now let us run the code and remember
this main method is actually the entry
point of your application so this method
will simply call add method which in
turn will simply print a plus B so let
us now run the code so in the output we
have sum is 6 and now let us make it
print line and then run the code again
so this makes our output better right
and now if you notice here this add
method does not return anything so here
you can also use colon space unit which
is actually equivalent to void in case
of Java now as per the cortland coding
convention you don't have to specify
unit if you don't return anything so
by default every method returns unit
that is mode so you can remove it and it
will work perfectly fine right and now
suppose I want to pass these two
variables as a parameter so for that
what I will do I will simply pass 2
comma 4 here and now let us remove these
two lines of code and then specify
variable a : of the type of int comma
where II will be : of the type of int
and now here I am simply printing out
the values inside the function add so
let us now run the code so this is how
we pass the argument in case of cortland
so sum is 6 right and now suppose our
requirement is that let us print this
statement inside the main method not
here that is we want in return the sum
of these two numbers so for that what I
will do is I will simply use where sum
equal to add two numbers and then I will
simply cut this statement and paste it
here and instead of this let us use
let's say dollar some cite the string
interpolation or alternatively you can
also use plus some write so no issue in
this as well now here I have to return
the sum of a and B so that I can print
it here right so for that I have to
simply return let's say return a plus B
and now it simply shows an error the
type mismatch now the return type is by
default is unit now here we are
returning the integer value so instead
of unit let us type capital I NT so this
method simply returns the sum of these
two numbers and store it inside the very
the variable sum and then we print it
out here so let us now run the code so
here we get sum is 6 so this was all
about the basic syntax for the functions
in case of Kotlin so catch you guys in
the next video thanks for watching have
a good day